class_docstr: Basic building block class for both :class:`BaseDataChunk` and :class:`BaseDataset`
  
  Notes
  -----
  Defines core callback method scaffolding, characterized by the following default behaviors:
      * Eight core callback methods call :meth:`BaseDataCore._on_call_default`
      * :meth:`BaseDataCore._on_call_default` does nothing
      * :meth:`BaseDataCore._do_something` calls the appropriate core callback method
code: def on_fold_end(self, *args, **kwargs):
      self._on_call_default("fold", "end", *args, **kwargs)
  
imports: import pandas
  from typing import List, Optional
label_desc: Use image node_id 6 for calling the BaseDataCore obj's underlying member method code with example usage: obj.on_fold_end() without return types